Glue fastening of superimposed leaves

ABSTRACT

A method of producing continuous and snap-out business forms, consisting of a plurality of properly aligned, superimposed sheets, cross perforated and interleaved with carbon paper, and especially adapted for use in data processing printers, wherein the glue lines are continuous, uniform and of minimal width and thickness, eliminating undue bulkiness and rigidity, and assuring complete and effective bonding throughout the length of the sheets.

Sept. 4, 1913 Original Filed Dec. 4, 1969 1 u .m e W 5 n NM 2 m w W m e n V 2 m w m m a Mm 0 m m o v m m flaw H mm 5 MM fi m M we PH Tm mag @x N VE N TOR-5 Larry B. Wo/fbe/g John Harper BY 1 ATTORNEYS.

United States Patent 3,756,889 GLUE FASTENING OF SUPERIMPOSED LEAVES Larry B. Wolfberg and John Harper, Wichita, Kans., assignors to Service Business Forms, Inc., Wichita, Kans. Continuation of abandoned application Ser. No. 882,256, Dec. 4, 1969. This application Dec. 20, 1971, Ser. No.

Int. Cl. B32b 31/12, 31/28 US. Cl. 156-253 5 Claims ABSTRACT OF THE DISCLOSURE A method of producing continuous and snap-out business forms, consisting of a plurality of properly aligned, superimposed sheets, cross perforated and interleaved with carbon paper, and especially adapted for use in data processing printers, wherein the glue lines are continuuous, uniform and of minimal width and thickness, eliminating undue bulkiness and rigidity, and assuring complete and effective bonding throughout the length of the sheets.

This is a continuation of application Ser. No. 882,256, filed Dec. 4, 1969 now abandoned.

In the manufacture of continuous business forms and the like it is extremely important that they be capable of use in automatic, computerized printers and other machines without creating any difficulty such as jamming, damage to the forms, malfunction of the machines or other problems. This necessitates high perfection in the production of the multilayered units whether in the nature of sheets or leaves used as business forms, stationary or otherwise.

By far the most difficult problem is in the line gluing of the sheets together. First of all, there must not be any undue bulkiness at the zone of the glue line. Secondly, the increase in thickness necessitated by the presence of the glue must be uniform and minimal. Thirdly, the glue line must be continuous in absence of spaces therealong Where complete interconnection of the sheets cannot be effected. Fourthly, the interconnection must not give way and permit separation of the sheets at any point along the glue line either during production, or during storage and shipment, or during use in printing machines or other equipment.

Conventionally, both the so-called hot and cold glues have been used for this purpose, including both animal and dextrin solutions. And various heating methods have been tried, including infrared thermal radiation to evaporate the liquid content of the glue and to, therefore, effect drying. But, except in cases of rather expensive, slow procedures, no prior method has been entirely successful regardless of the type of glue or heating methods employed.

Particularly aggravating has been the problem known as tenting" and the problem of build-up bulk caused by the line of glue. The continuous, multicopy sheets to which the present invention relates are folded transversely at equally spaced intervals to present a finished pack which can not only be conveniently stored and shipped but which will automatically unfold as the same is fed to computerized printers, typewriters and other machines. Defective gluing results in separation of the sheets at each line of fold, forming a small triangular bulge known as a tent. Such condition cannot be tolerated primarily because of malfunction in the aforementioned machines with which the forms and the like are ultimately used.

Still another problem in the assembly and fastening of a number of continuous leaves of paper for use as above explained relates to maintaining the sheets in proper alignment. Consequently, each layer must be rather perfectly aligned, edge to edge, with proximal sheets thereabove and therebelow so that all material printed or typed on the ice original will be reproduced on the copies, by the effect of interleaved carbon, mechanical or chemical self-contained reproducing paper, in substantially the same location marginally as well as top to bottom. Conventional methods of assembly and interconnection of such continuous, superimposed leaves or sheets of paper through use of glue have not always solved this problem to the complete satisfaction of all users.

It is, therefore, the primary object of the present invention to provide a rapid and inexpensive gluing method which will solve all of the above problems and difiiculties.

The most important object of the instant invention is the provision of a method of producing continuous business forms and the like which will present a glue line that eliminates all danger of tenting at the lines of fold.

Another important object of our present invention is to provide a method of gluing which eliminates undue bulkiness at the glue line.

Still another important object is the provision of a method of the kind above described which assures complete bonding of the sheets together throughout the length of the glue line in complete absence of skips occasioned by absence of glue or by its ineffectiveness in holding the sheets against separation.

A further important object of the present invention is to provide a method which will produce business forms that can be successfully used with computerized printers and other equipment in total absence of difficulties because of the nature of the forms themselves.

A still further object is to provide a method of producing a glue line of uniform, minimal width and thickness that is continuous and capable of effecting sufficient surface impregnation of the paper fibers to assure complete and adequate bonding throughout the length of the sheets.

It is an important aim of our invention also to provide a method which eliminates undue rigidity and inflexibility of the sheets along the glue line, in total absence of dried glue crystals or lumps which preclude uniform thickness of the sheets at the glue lines and are ineffective in causing the sheets to be bonded together at such lumps.

Another aim of the present invention is to provide proper alignment of the sheets throughout the time the method is carried out and until the glue is fully set and dried so as to hold the sheets against relative slippage.

Other objects and aims will be made clear or become apparent as the following specification progresses, reference being had to the accompanying drawing, wherein:

FIG. 1 is a schematic, side elevational view of equipment capable of use in carrying out the method of glue fastening of superimposed leaves in accordance with the concepts of our present invention;

FIG. 2 is a schematic top plan view of the equipment illustrated in FIG. 1;

FIG. 3 is a perspective view of a pack of continuous business forms or the like, partially unfolded and with one corner pulled back for illustrating certain details of construction;

FIG. 4 is a fragmentary, top plan view of the forms shown in FIG. 3, the aforementioned corner being broken away for clearness;

FIG. 5 is a transverse cross-sectional view through the forms illustrated in FIG. 3;

FIG. 6 is a fragmentary, longitudinal cross-sectional view through the forms showing one type of cross perforator; and

FIG. 7 is a cross-sectional view through one of the nozzles employed in the equipment shown by FIGS. 1 and 2 for depositing a line of glue onto the sheets as they are advanced through the collator.

For convenience, the method of our present invention will hereinafter be described in connection with the production of a pack of continuous business forms 12 having equally spaced transverse lines of perforation 14, and especially adapted for use in computerized or data processing printers and other comparable equipment. It is to be understood, however, that such terminology does not preclude advantageous use of our method in connection with the glue fastening of superimposed leaves or sheets of paper having various other uses, including, therefore, stationery and other products.

The form chosen for illustration of our method, broadly designated by the numeral 12 as aforesaid, includes a top sheet or leaf of paper 16, a sheet of carbon paper 18 attached to the sheet 16 therebelow, a second sheet of paper 20 beneath the carbon 18, a second sheet of carbon paper 22 beneath the sheet 20 and attached thereto, and a third or bottom sheet of paper 24 beneath the carbon 22. It is to be understood, however, that in accordance with the method about to be described, the forms 12 may consist of any number of additional sheets as at 16, 20, and 24 with a corresponding number of carbons as at 18 and 22. Moreover, it is not necessary, within the principles of our invention, that the pack 10 include the carbons 18 and 22, or any carbons, as in the case of self-contained reproducing paper, nor do we deem ourselves limited to the lines of perforation 14 because such perforated lines 14 may be eliminated or the continuous sheet 16 and/or sheets 20 and 24 may be entirely severed at the lines indicated by the numeral 14.

Moreover, the product shown in FIGS. 3, 4 and 5 may have rows of holes or openings 26 and 28 adjacent the longitudinal edges of the sheets 16, 20 and 24, but since the carbons 18 and 22 do not extend the full width of the sheets 16, 20, and 24, the holes 26 and 28 do not pass through the carbon paper.

Furthermore, the product chosen for illustration is provided with a longitudinal line of perforations 30 which pass through all of the sheets 16, 18, 20, 22 and 24, presenting a marginal stub 32 which may be snapped away after processing through the printer, thereby separating all of the sheets 16, 18, 20, 22 and 24, and permitting desired distribution of the individual sheets 16, 20 and 24 when the same are torn apart along the lines of perforation 14.

To this end, therefore, the carbons 18 and 22 are attached to their corresponding sheets 16 and 20 respectively by longtiudinal lines of glue 34 within the stub portions 32, i.e., outwardly of but adjacent the line of perforation 30. On the other hand, the sheet 16 is fastened to the sheet 20, and the sheet 20 is fastened to the sheet 24 by glue lines 36 extending continuously throughout the length of the stub 32 adjacent the outermost longitudinal edge thereof with the holes or openings 28 located between the glue lines 34 and 36. Our present invention relates essentially to the proper formation of the glue lines 36, as will hereinafter appear.

In FIGS. 1 and 2 of the drawing, a collator broadly designated by the numeral 38 supports supply drums 40, 42, 44, 46, and 48 for the continuous sheets or leaves 16, 18, 20, 22, and 24 which are advanced horizontally (from right to left viewing FIGS. 1 and 2), to place such sheets in superimposed relationship, by rotatable drive rollers 50 which may or may not have radial pins at their peripheries for receiving the holes 26 and 28 of the sheets 16, 20, and 24.

Collator 38 is equipped with a number of special nozzles 52 for depositing a line of glue on the sheets during their advancement. Such nozzles 52 are especially formed in accordance with the present invention, preferably from a nonoxidizing, malleable or nonmalleable material capable of receiving copies of required dimensions, as illustrated in FIG. 7 in the drawing. It is extremely important that the nozzle 52 direct a very fine stream of glue to the sheets, and while we have been successful in carrying out our method by the selection of an orifice 54 for the nozzles 52 that has a size in the order of from .005 to .0937 inches, our invention is not necessarily restricted to such dimensions.

Moreover, in order to cause the glue to rise and string out before reaching the sheets, thus forming narrower glue lines 36 of minimum thickness than is made possible by a standard nozzle, we have cut the head 56 of the nozzle 52 at an angle of approximately 5, the sheets traveling with respect to the head 56 in the direction of arrow 58 in FIG. 7.

We have found that the so-called hot glue universally used in many applications within this field are not entirely satisfactory for use in connection with our present method for many reasons including the fact that such glues must be reduced both in temperature and in moisture content before they etfectively bond the sheets together and there is no satisfactory drying and cooling means for such glues which will permit high speed production at relatively low manufacturing costs. Moreover, the hot glues form a jell on reduction of temperature, causing them to grab onto the fibers of the paper too quickly, thereby aggrevating the problem of maintaining the sheets in proper alignment, i.e., with their holes 26 and 28 in full and direct register.

We have also determined that the conventional animal and dextrin glues are not entirely satisfactory because of the fact that solids are in suspension within the liquid content thereof such that glues of that type are too slow to set up and dry and not conducive to obtaining the rather large number of desired results made possible through use of our present method.

Therefore, in accordance with our invention, the glue to be dispensed from the nozzles 52 is desirably a cold glue that is easy to handle, requiring no heat to maintain it in a fluid condition and requiring no equipment for reduction of the temperature thereof, it being contemplated that the glue emanating from the nozzles 52 be at room temperature. In this connection we prefer to use an emulsion having a polyvinyl base with a water content of approximately 40%, including the usual plastercizers, and having the polyvinyl acetate solids emulsified therein, as distinguished from dextrin and animal solutions, wherein the solid particles are in ordinary suspension.

Depending upon the base resin, such glues tend to set rather quickly, particularly upon application of pressure, and thereupon are capable of rapid evaporation of their moisture content. Therefore, as soon as the sheets 20 and 24 come into engagement with the glue lines 36 thereabove, such glue tends to immediately grab onto the fibers of the papers and hold them against slippage relatively, but, by the same token, the selected glue is characterized by the fact that sufiicient relative slippage between the sheets 16, 20, and 24 is permitted to maintain the holes 26 and 28 aligned and in register while the remaining steps of the process are carried out.

In accordance with our method also, we prefer to use pulsed microwave energy to generate internal heating of the glue in a concentrated area which may be confined to approximately inch wide or less, thereby causing rapid drying and bonding in the stub construction 32 of continuous as well as snap-apart business forms and stationery. Such microwave internal heating in a concentrated area, as distinguished from induced heating over the entire form area, can be produced through use of magnetron 60 in which the flow of electrons is controlled by an externally applied magnetic field to generate power at microwave frequencies, such very short electromagnetic waves normally being between approximately centimeters and one centimeter in wave length. Such microwaves, in the vicinity of about 2,400 megacycles, are capable of developing tremendous heat and energy, combined in a relatively small space conducted to the exact zone where heat is needed without introduction of undesired heat into those areas of the sheets where the paper and the carbon might be adversely affected, which has been a detriment to optimum results in all previous systems and methods. Accordingly, the wave guide section 62 of the magnetron generator 60 need not exceed more than approximately four feet in length thereby reducing the drying time to a minimum and permitting high speed production. Such internal heating of the glue to evaporate its moisture content prevents damage to the carbon papers 18 and 22 because their oil based carrying agent will not dry out, nor will there be any spoilage of the paper sheets 16, 20, or 24 by burning or scorching.

It has been found advisable also to use pinned drums, rollers or the like 64 at the drying section to move the superimposed sheets simultaneously along the section 62 and maintain them in proper alignment until such time as the glue is completely dry and full and effective bonding of the sheets together has been effected. As above mentioned, the glue which we have selected permits sufficient slippage of the sheets relatively to cause such proper alignment during first contact of the paper parts. Yet, because of the fast setting characteristics of the glue after water has been removed by microwave created heat, the complete, firm and final fastening of the sheets one to another is made possible during the very short period during which the glue lines 36 are subjected to the generator 60.

From the dryer 60 the sheets are advanced through a perforating head 64 to produce the transverse lines of perforation 14. It is of course possible to interpose the head 64 ahead of the dryer 60, but the step of perforating tends to shift the sheets out of alignment and we have, therefore, found it to be preferable to have complete and firm bonding of the sheets prior to subjecting them to the perforator 64.

In FIG. 6 of the drawing there is illustrated upper and lower perforating drums 66 and 68 provided with diametrically opposed perforating blades 70 and 72 respectively and timed in their rotation such as to alternately perforate the sheets along the lines 14 from the top and from the bottom. Such alternating function of the drums 66 and 68 of the head 64 is advantageous from the standpoint of proper folding in folder section 74 along the lines 12 to produce the pack as shown in FIG. 3. Alternately the drum 68 could be in the form of an anvil with all of the blades on the drum 66 such that formation of the lines 14 would be from the top only, but such arrangement causes a back-fold on every other cross perforation which limits the number of superimposed sheets to no more than eight and in turn is less desirable than drums of the kind illustrated at 66 and 68 in FIG. 6 of the drawing.

It is now apparent that with the sheets 16, and 24 fully and properly bonded together along the glue lines 36, there will be no separation or tenting at the lines of fold along the perforation lines 14, eliminating, therefore, the problems of jamming and other malfunctions which are quite common in the use of a product of this nature in printing machines and other equipment.

In order to accomplish the desired results as hereinabove initially outlined, it is also extremely important that the glue lines 36 be very narrow and of minimal thickness for many reasons. By providing for only sufiicient surface impregnation of the paper fibers such as to effect good bonding, the stub area 32 will not become unduly rigid and inflexible along the glue lines 36, not only making it possible to form the sheets into a compact stack 10, but reducing problems incident to the feeding of the forms through computerized printers and the like. Such minimum bulkiness at the glue lines 36 is made possible by applying the glue continuously and uniformly and by selection of a glue nozzle, as well as a drying process, which will eliminate zones of separation along the glue lines 36 and eliminate formation of dried glue crystals, lumps and the like which are incapable of holding the sheets properly bonded together.

It is to be understood also that our method is not limited to the use of the glue line 36 only along one longitudinal edge of the forms 12; in certain instances it is des rable or necessary to duplicate the glue applying and drying steps along that edge of the forms 12 having the openings or holes 26 therein. Our invention is also fully adaptable for use in making various types of snap-out forms, as above indicated. Moreover, it is not necessary to utilize the stub feature 32 with the line of perforations 30 in the manner and for the purpose above described.

Concentrated heating along the glue lines 36 is important because it avoids damage to the carbons 18 and 22. In some instances, processed carbons are used having the same width as the sheets 16, 20 and 24 with the holes 26 and 28 also passing through the carbon sheets. However, the marginal edges are kraft paper, not carbonized; hence, even 1n such instances our method will not damage the adjacent carbon areas.

Our invention also contemplates a complete and proper method of fastening the entire set of forms together by the application of the glue lines to the face and back of paper sheet 20, whereby the glue lines are applied so as to fasten the paper to the carbon below, and this carbon in turn is fastened to the sheet below it, thus accomplishing the manufacture of extremely flexible forms which will allow the complete set to pass easily around the platen of a typewriter or a computer printer which'utilizes a small round platen and, therefore, is more prone to jam when a bulky form is pased over and around the small platen. This is to be done by the use of processed carbon paper with the holes 26 and 28 also passing through the carbon sheets, thus allowing the pins on the drums to function in their capacity of moving the sheets forward while the gluing and drying functions are being performed. Under special conditions where a wider stub is perimssible, this form of construction can be effected without the use of the holes 26 and 28 in the carbon, by moving the carbon away from the edge and applying the glue and microwave heat to the form on the inside areas of the pin feed device.

Important also is the fact that our method may be accomplished without the necessity of using slow speed zigzag type folders with tucker blades, thereby enabling the use of high speed folding equipment such as, but not limited to, spiral and/or air jet or vacuum type folders operating at their fullest rated speed and capacity.

While application of the adhesive in the form of a continuous, elongated, narrow, thin line, which is preferred, our invention is also adaptable to spot gluing or to interrupted lines. In certain instances it may be desirable for example, to omit the glue at the lines of fold.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A method of producing an elongated, continuous, folded web having at least one pair of face-to-face, fibrous, printable sheets adhesively joined along one marginal edge of the web and capable when unfolded of trouble-free use in data processing printing machines, said method comprising the steps of:

rapidly and continuously advancing both sheets along a linear path of travel;

continuously dispensing a cold glue from a nozzle in a fine stream,

said glue being at room temperature and in liquid form, being essentially free of suspended solids, having a fiber impregnation capability and being a plasticized polyvinyl acetate base adhesive in emulsified form having a water content of approximately 40%;

depositing the dispensing glue onto the inner face of one of said sheets along one of its marginal edges during uninterrupted advancement to form a tacky glue line on said face having a uniform width and thickness;

controlling said dispensation of the glue by restricting the size of the discharge orifice of said nozzle to a size which is substantially on the order of from .005 to .0937 inch to limit the thickness and width of said glue line accordingly, thereby minimizing bulkiness in the web along said one marginal edge thereof; thereupon immediately moving the sheets into aligned, face-toface interengagement as the same are advanced to cause the glue of said line to grab onto the fibers of the sheets and hold the latter in substantial alignment, yet permit the sheets to be shifted relatively for continuous correction of alignment before drying and final set of the glue; then immediately subjecting the glue line to the high energy, microwave, pulsed frequencies emanating from a magnetron generator while maintaining the sheets shifted into alignment as the same are advanced,

said glue being characterized by its capability of evaporation of its water content and immediate drying while subjected to said energy,

said energy being wholly concentrated to the area of said glue line for instantaneously creating a molecular agitation in the glue emulsion and thereby generating sufficient heat within the body of the glue line to quickly boil away its water content without any burning or scorching of the sheets, or deleterious effects upon the chemical or physical properties of the glue itself;

cross perforating said sheets; and

subjecting said sheets to a high speed transverse folder to present a pack of said sheets folded along transverse lines,

said microwave emanations extending along the path of travel of the sheets a sufiicient distance to completely dry the glue and effect impregnation of the glue into said fibers suflici ently to prevent bulkiness and inflexibility along the glue line without interruption in the continued, rapid advancement of the sheets, presenting a complete, continuous, tight bond firmly uniting the sheets throughout the entire length of the sheets and the glue line such that the bond is capable of maintaining the joinder without breakage of the bond, without tenting at the lines of fold, without jamming of said folder upon said subjection of the web to transverse folding by the folder across the dried glue line, and without jamming of said data processing printing machines when the web is subjected to printout operations.

2. A method as claimed in claim 1 and bringing the sheets into said relative alignment during advancement but prior to drying of the glue by advancing the sheets through use of pinned drives engaging within holes in said sheets, permitting said relative shifting of the sheets while the glue line is tacky.

3. A method as claimed in claim 1 continuously advancing a reproducing medium with the sheets simultaneously with said advancement of the latter; and concentrating said energy as well as continuously controlling the intensity thereof sufliciently to avoid deleterious effects upon said medium.

4. A method as claimed in claim 1 further controlling said dispensation of the glue by maintaining the sheets, during advancement, above an uppermost head of said nozzle for upward flow of the glue from the nozzle to said inner face of said one sheet; and maintaining said inner face in spaced relationship to at least a portion of the head by utilization of a head having an angle of approximtaely 5 with respect to said face whereby to cause the glue to rise and string out before reaching said face.

5. A method as claimed in claim 4 wherein said angle is in the direction of advancement of the sheets and the slope of said head is upwardly toward the zone of gluedrying whereby the glue tends to discharge downwardly and rearwardly of said direction of advancement.

References Cited UNITED STATES PATENTS 2,605,120 7/1952 Breen 282- R 3,298,353 1/1967 Hoffman 1l8411 3,397,418 8/1968 Steadman et a1 1l8-411 OTHER REFERENCES Engineering Abstracts, Possible Uses of Microwaves For Industrial Heating, Marcum et al., Product Eng. January 1947.

ALFRED L. LEAVITT, Primary Examiner C. WESTON, Assistant Examiner US. Cl. X.R. 

